The animals for Hanna's upcoming visit haven't been announced, but last year's collection included Fennec fox kits, a 15-foot python, a Siberian lynx, a lemur, a lesser anteater, a penguin, a beaver, a young wallaby and a 6-week-old black bear, according to the aquarium.

Jennifer Herring, aquarium president, called Hanna a "highlight" of the institution's speaker series last year.

"While we enjoyed his presentations immensely, we were equally charmed and impressed by how he graciously greeted everyone from the audiences afterward, especially young kids," she said. "Those personal connections can be so inspirational as he -- and the Maritime Aquarium -- seeks to recruit new stewards of the environment."

Raising bluegills in the family bathtub as a kid, Hanna went on to become a director emeritus of the Columbus Zoo, hosts two weekly TV shows and is a frequent guest on "Good Morning America," "The Late Show with David Letterman" and other programs.